JP4279759B2 - Cooling device for internal combustion engine - Google Patents

Description

  The present invention relates to a cooling device for an internal combustion engine that cools the internal combustion engine using a water jacket surrounding a cylinder liner that forms a plurality of cylinder bores.

  In many reciprocating multi-cylinder internal combustion engines, a water jacket is formed so as to surround a cylinder liner that forms a plurality of cylinder bores arranged in the front-rear direction on a cylinder block, and cooling water is supplied from one end side to the other end side of the water jacket. A cooling structure that cools the cylinder liner by allowing it to flow is adopted.

  In such a cooling structure, the water jacket is not changed in the water jacket so that the flow rate and flow velocity of the cooling water flowing through the water jacket can be easily controlled for each model of the internal combustion engine. A spacer that partitions the width direction is provided to partition the water jacket into an inner passage (hereinafter referred to as an inner passage) and an outer passage (hereinafter referred to as an outer passage).

  By the way, the cylinder block is likely to accumulate heat between the cylinder bores due to its structure. In particular, in a cylinder type cylinder block in which adjacent cylinder bores are connected, the cylinder liner portion between the cylinder bores tends to be hotter than the other portions.

  In view of this, the temperature rise between the cylinder bores is suppressed by communicating the portion located between the cylinder bores of the water jacket with the cooling water passage on the cylinder head side to ensure the circulation of the portion.

  However, in the water jacket divided by the spacer, the flow rate and flow velocity of the cooling water flowing on the downstream side of the inner passage are reduced, and the cooling performance of the downstream cylinder liner tends to be insufficient. This is significant at the top of the cylinder liner near the combustion chamber.

Therefore, in order to supplement the cooling performance, with respect to the cylinder block partitioned by the spacer, a plurality of through holes are provided in almost the entire area of the spacer portion on the upper side of the spacer, and the cooling water flowing above the outer passage remains as it is in the inner passage. A technique to be introduced has been proposed (see Patent Document 1).
JP 2003-262155 A

  According to the technique disclosed in Patent Document 1, the flow rate and flow velocity of the cooling water that flows through the inner passage certainly increases. However, since Patent Document 1 has a structure in which cooling water is simply introduced from the outer passage to the inner passage, there is a strong tendency that the cooling water passing through the upper portion where the calorific value of the cylinder bore is large is supplied as it is to the upper portion of the downstream cylinder bore. The downstream cylinder liner is unlikely to exhibit a sufficient cooling effect. For this reason, it is difficult to cool the downstream cylinder liner as much as the upstream cylinder liner, and the upper portions of the front and rear cylinder liners cannot be uniformly cooled.

  Accordingly, an object of the present invention is to provide a cooling device for an internal combustion engine that can cool an upper portion of a downstream cylinder liner in the same structure as an upstream cylinder liner in a structure in which a water jacket is defined by a spacer. is there.

In order to achieve the above object, the invention according to claim 1 is a direction in which cooling water flows among spacers that divide the inside of a water jacket surrounding a cylinder liner forming a plurality of cylinder bores into an inner passage and an outer passage. In the spacer portion which is in the middle of the above, an introducing means for introducing the cooling water flowing in the outer passage into the inner passage from the upper portion of the spacer portion while being directed upward is provided. The introduction means has an opening part at least partially located on the side of the upper end part of the cylinder liner by cutting out the upper end part of the spacer, and the introduction means includes cooling water flowing through the outer passage. A part of the coolant is directed upward, and the cooling water that has reached the side of the upper end of the cylinder liner in the upward flow is directed from the side toward the upper end of the cylinder liner through the opening. Supply.

  The invention described in claim 2 employs a simple structure such as a slit-like opening cut out obliquely downward from the upper end surface of the spacer toward the upstream side in the flow direction of the cooling water.

  According to the third aspect of the present invention, as the introduction means, the cooling water flowing in the outer passage extending obliquely upward from the upstream side to the downstream side in the flow direction of the cooling water formed on the side surface of the spacer facing the outer passage. A simple structure including an inclined base portion that is directed upward, and an opening that is formed at the upper portion of the spacer while being connected to the end of the inclined base portion, and that introduces cooling water that is directed upward into the inner passage. It was adopted.

  According to a fourth aspect of the present invention, a protrusion is formed at the upper end of the spacer located on the upper side of the inclined base portion to prevent the cooling water from entering the inner passage from entering the inner passage, Further, before reaching the opening, it is configured not to enter the inner passage unnecessarily.

  According to the first aspect of the present invention, a part of the cooling water in the outer passage, particularly the cooling water having a relatively low water temperature passing through the lower side is introduced into the inner passage while being directed upward from the middle of flowing through the outer passage. Is done. As a result, the flow rate and flow rate of the cooling water can be compensated from the middle of the inner passage, that is, the downstream side where the flow rate and the flow rate decrease. The upper part of the side cylinder liner can be cooled.

  Therefore, the upper part of the downstream cylinder liner is cooled in the same manner as the upstream cylinder liner, and the upper part of each cylinder liner from the upstream side to the downstream side can be cooled uniformly.

  According to the second and third aspects of the invention, in addition to the above effects, the cooling water can be introduced by an upward flow with a simple structure.

  According to the invention described in claim 4, in addition to the above effect, the upward cooling water flowing through the inclined base portion is introduced into the inner passage while being concentrated and further accelerated by the protrusion. Thus, the upper part of the cylinder liner close to the combustion chamber can be effectively cooled.

[First Embodiment]
Hereinafter, the present invention will be described based on a first embodiment shown in FIGS.

  FIG. 1 shows a part of a multi-cylinder bore water-cooled internal combustion engine, for example, a 4-cylinder bore reciprocating internal combustion engine, and FIG. 2 shows a partial cross section of the internal combustion engine (cross section taken along the line AA in FIG. 1). In the figure, reference numeral 1 denotes a cylinder block. As the cylinder block 1, for example, a thyme type is used in which four cylinder liners 2a to 2d are continuously arranged in the front-rear direction. Four cylinder bores 3a to 3d arranged in the front-rear direction are formed on the head of the cylinder block 1 from the cylinder liners 2a to 2d adjacent to the front and rear. A piston (not shown) is housed in each of the cylinder bores 3a to 3d so as to be able to reciprocate. In addition, a cylinder head 5 having a combustion chamber, a valve mechanism, a spark plug, an injector, and the like assembled in each cylinder bore 3a to 3d, for example, is shown in the upper part of the cylinder block 1 (illustrated by a two-dot chain line in FIGS. 1 and 2). ) And a piston that reciprocates in each of the cylinder bores 3a to 3d is configured to output a shaft output from a crankshaft (not shown). A gasket 6 (shown by a two-dot chain line in FIG. 2) is interposed between the head of the cylinder block 1 and the cylinder head 5.

  The cylinder block 1 is formed with a water jacket 7 constituting a cooling device. The water jacket 7 is formed of a groove portion having a predetermined width that surrounds the cylinder bores 3a to 3d as shown in FIGS. For example, the groove has a depth up to approximately the midpoint of the length of the cylinder bores 3a to 3d. One end of the water jacket 7 communicates with a cooling water inlet 8 formed at the front of the cylinder block 1, for example. The cooling water inlet 8 communicates with one end of a water jacket 9 (illustrated by a two-dot chain line in a part of FIG. 2) formed in the cylinder head 5 so that the cooling water is in the water jacket of the cylinder block 1. 7. It is structured to flow into both the water jacket 9 of the cylinder head 5. The other end of the water jacket 7 is configured to flow out from a cooling water outlet (not shown) formed at the rear of the cylinder head 5 through, for example, the other end of the water jacket 9 of the cylinder head 5.

  In the water jacket 7, a water jacket spacer 10 (hereinafter simply referred to as a spacer 10; corresponding to the spacer of the present application) is accommodated.

  For example, as shown in FIG. 2, a part having an outer shape that occupies substantially the entire region in the middle in the thickness direction of the groove portion of the water jacket 7 is used for the spacer 10. Specifically, the spacer 10 includes, for example, four water-thin cylindrical portions 4a to 4d that are slightly shorter than the depth of the water jacket 7 as shown in FIG. A part having an outer shape that occupies the middle in the width direction of the jacket 7 is used. As shown in FIG. 2, the spacer 10 is accommodated between the bottom of the water jacket 7 and the gasket 6, and defines the width direction in the water jacket 7. With this section, an inner passage 11 is formed between the cylinder liners 2 a to 2 d and the spacer 10, and an outer passage 12 is formed between the opposite spacer 10 and the outer wall surface of the water jacket 7. Thereby, most of the cooling water from the cooling water inlet 8 flows into the outer passage 12, and a part flows into the inner passage 11 through a gap existing around the spacer 10. With this structure, it is possible to control the flow rate and flow velocity of the cooling water flowing through the water jacket 7 for each model of the internal combustion engine only by changing the spacer 10 without changing the water jacket 7. Of the inner passage 11, the passage portion disposed in the hollow portion between the cylinder liners 2 a to 2 d is formed with a drain hole 13 (through hole formed in the gasket 6 as shown by a two-dot chain line in FIGS. 1 and 2. Through the hole), the coolant is communicated with the water jacket 9 of the cylinder head 5 so that the cooling water is passed to the portion between the cylinder bores where heat is likely to be trapped.

  Further, as shown in FIGS. 1 and 3 to 5, outflow of cooling water from the drain hole 13 is caused, for example, on the spacer portion having a particularly large cooling load, specifically, on the exhaust portion. A supplementary upward introduction structure (corresponding to the introduction means of the present application) is provided. In this structure, for example, a slit 15 (corresponding to the slit-shaped opening of the present application) is used. Specifically, the slit 15 is a part where the flow rate or flow rate of cooling water flowing through the water jacket 7 is reduced, for example, the drain hole 13 between the front cylinder bores 3a and 3b, and the central cylinder bores 3b and 3c. It is provided in the peripheral wall part of the cylindrical part 4b located between the drain holes 13 between. For example, as shown in FIG. 4, the slit 15 has a structure in which the slit 15 is elongated in an obliquely downward direction from the upper end surface of the peripheral wall portion of the cylindrical portion 4 b toward the upstream side in the flow direction of the water jacket 7. ing. The lower end of the slit 15 extends to a region where cooling water having a low water temperature flows, for example, near the center of the height of the peripheral wall portion of the cylindrical portion 4b. The slanted slit 15 changes the part of the cooling water flowing through the outer passage 12 to the upward flow with the wall surface of the slit 15 as a guide, and through the opening of the slit 15, It is structured to be introduced into the inner passage 11 from above.

  According to the cooling apparatus for an internal combustion engine configured as described above, most of the cooling water flowing into the cylinder block 1 from the cooling water inlet 8 is outside as shown in FIGS. 5 (a) and 5 (b). It flows into the passage 12. Also, a slight flow rate flows into the inner passage 11 through the gap around the spacer 10. These cooling water flows to the other end side which becomes the exit side of the water jacket 7, and cools the upper portions of the cylinder liners 2a to 2d which generate a large amount of heat.

  Here, the cooling water in the inner passage 11 flows out to the cylinder head 5 from between the cylinder bores 3 a to 3 d through the drain holes 13 of the gasket 6. The heat accumulated between the cylinder bores is cooled by the flow of the cooling water. Due to the water flow between the cylinder bores, the flow rate and the flow velocity of the cooling water flowing through the inner passage 11 decrease from the middle.

  At this time, a slit 15 extending obliquely from the middle stage to the upper end is formed in the spacer 10 at a point where the flow rate or flow velocity of the cooling water starts to decrease, as indicated by the arrows in FIGS. 4 and 5A. Has been. Thereby, the cooling water flow including the cooling water having a low water temperature passing through the lower side of the outer passage 12 (part away from the combustion chamber) is forcibly changed to the upward flow by the wall surface of the slit 15, It is introduced into the upper part of the inner passage 11 through the opening.

  Thereby, the flow rate and flow velocity of the cooling water in the inner passage 11 are recovered. The cooling water in the outer passage 12 is supplemented by the supply from the cooling water outlet 9 accordingly.

  At this time, the cooling water having a low water temperature introduced into the inner passage 11 flows along the upper end of the liner and the lower surface of the gasket 6 due to the upward flow. Then, in the inner passage 11, a flow that promotes cooling is generated near the upper end of the liner closest to the combustion chamber. Due to the introduction of the cooling water having a relatively low water temperature and the generation of a water flow near the upper end of the liner, the upper portions of the cylinder liners 2c and 2d on the downstream side are effectively cooled, and the cylinder liners 2c and 2d are on the upstream side. The cylinder liners 2a and 2b are cooled in the same manner.

  Therefore, the upper portions of the cylinder liners 2a to 2d are uniformly cooled from the upstream side to the downstream side, and the temperature in each of the cylinder liners 2a to 2d can be made uniform. In addition, since the structure for directing the cooling water upward is a structure in which the oblique slits 15 are provided, the structure is simple and the cost burden can be reduced.

  In addition, although the slit 15 was provided in the surrounding wall part of the cylindrical part 4b surrounding the cylinder liner 2b of the downstream side among the spacers 10, not only this but other downstream cylinder liners, for example, the cylinder liner 2c and the cylinder bore 2d, You may provide in the surrounding wall part of the cylindrical part which surrounds.

[Second Embodiment]
6 to 9 show a second embodiment of the present invention.

  In the present embodiment, the upward introduction structure of the cooling water is configured using a slope structure instead of the slit as shown in the first actual form.

  Specifically, in the upward introduction structure of the present embodiment, as shown in FIGS. 6 to 9, the outer surface of the peripheral wall portion of the cylindrical portion 4b surrounding the downstream cylinder liner 2b (the surface facing the outer passage 12). For example, an elongated shape extending from the vicinity of the center in the height direction (region where cooling water having a low water temperature flows) to the vicinity of the upper end of the peripheral wall portion of the cylindrical portion 4b while extending obliquely upward toward the downstream of the cooling water flow direction. The base part 20 (corresponding to the inclined base part) is formed with, for example, a square notch formed at the upper end of the peripheral wall portion of the cylindrical part 4b with the lower edge connected to the end of the base part 20. A structure combining the inflow opening 21 is used.

  That is, the structure forms an elongated inclined surface 20a facing the cooling water flow direction, and the inclined surface 20a allows the cooling water including the low water temperature of the outer passage 12 to be directed upward from the opening 21 while passing the cooling water upward. It has been introduced to. Even with this configuration, the cooling water in the outer passage 12 can be introduced into the inner passage 11 while being changed to an upward flow.

  Further, in the present embodiment, in addition to this, at the upper end portion of the peripheral wall portion of the cylindrical portion 4b, a protruding portion that protrudes toward the outer passage 12, for example, an eave portion 22 is formed in the region where the base portion 20 is present. This eaves part 22 suppresses the coolant flowing through the base part 20 from entering the inner passage 11 unnecessarily. When this eaves portion 22 is used in combination, the upward cooling water flowing through the base portion 20 is concentrated and further accelerated toward the opening portion 21 as shown by the arrows in FIGS. Since it is introduced into the passage 11, the upper portions of the cylinder liners 2c and 2d on the downstream side, particularly the end portion closest to the combustion chamber, can be effectively cooled. In addition, the opening edge 21a opposite to the inclined surface 20a of the opening 21 is formed thin so that the accelerated cooling water can be introduced into the inner passage 11 satisfactorily.

  However, in the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  The present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention. For example, in the above-described embodiment, an example in which the upward introduction structure is provided on the exhaust side, which is considered to generate a large amount of heat, among spacers has been described. However, the present invention is not limited thereto, and an upward introduction structure may be provided on the intake side. Good. Of course, you may provide the opening part 21 of 2nd Embodiment mentioned above in 13 vicinity between cylinder bores.

The perspective view which shows the cooling device of the internal combustion engine which concerns on the 1st Embodiment of this invention. Sectional drawing which follows the AA line in FIG. The disassembled perspective view which shows the external appearance of the spacer of the cooling device with the cylinder block to which the spacer is assembled. The perspective view which expands and shows the slit which changes to an upward flow. The figure explaining the time when the cooling water which flows through an outer side passage is changed into an upward flow by a slit, and is introduced into an inner side passage at the time of distribution of a water jacket. The disassembled perspective view which shows the external appearance of the spacer used as the principal part of the 2nd Embodiment of this invention with the cylinder block which the same spacer assembles | attaches. The perspective view which looked at the same spacer from a different direction. The figure explaining the cooling water which flows through an outer side passage at the time of distribution | circulation of a water jacket being changed into an upward flow by an inclined base part and an eaves part, and being introduced into an inner side passage. The perspective view which expands and shows the inclination base part changed into an upward flow, and the protrusion part which suppresses that cooling water approachs an inner side channel | path.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Cylinder block, 2a-2d ... Cylinder liner, 3a-3d ... Cylinder bore, 5 ... Cylinder head, 6 ... Gasket, 7 ... Water jacket, 10 ... Water jacket spacer (spacer), 11 ... Inner channel, 12 ... Outer channel , 15 ... slits, 20 ... pedestals (inclined pedestals), 21 ... openings, 22 ... eaves (projections).

Claims (4)

Around the cylinder liner forming a plurality of cylinder bores arranged in the front-rear direction, a water jacket is formed so that cooling water can flow from one end side so as to surround each cylinder liner, and an inner passage and an outer passage in the water jacket In the cooling device for an internal combustion engine configured by providing a spacer partitioned into
The spacer, the from the bottom of the water jacket and has a contour which reaches to the side how the upper portion of the cylinder liner, the to parts of the flow direction during the cooling water, before the part of the cooling water flowing through the outer passage Introducing means to introduce into the inner passage ,
The introduction means has an opening part at least partially located on the side of the upper end part of the cylinder liner by cutting out the upper end part of the spacer, and the introduction means includes cooling water flowing through the outer passage. A part of the coolant is directed upward, and the cooling water that has reached the side of the upper end of the cylinder liner in the upward flow is directed from the side toward the upper end of the cylinder liner through the opening. A cooling device for an internal combustion engine, characterized by being supplied . 2. The internal combustion engine according to claim 1, wherein the opening is formed in a slit shape that is cut obliquely downward from the upper end surface of the spacer toward the upstream side in the flow direction of the cooling water. Cooling system. The introduction means is formed on the side surface of the spacer facing the outer passage so as to extend obliquely upward from the upstream side to the downstream side in the flow direction of the cooling water, and directs the cooling water flowing through the outer passage upward. has a ramp portion that, the opening, according to claim 1, characterized in that said continuous with the ends of the ramp portion is formed on an upper portion of the spacer, thereby introducing cooling water toward upward into the inner passage A cooling apparatus for an internal combustion engine according to claim 1. Around the cylinder liner forming a plurality of cylinder bores arranged in the front-rear direction, a water jacket is formed so that cooling water can flow from one end side so as to surround each cylinder liner, and an inner passage and an outer passage in the water jacket In the cooling device for an internal combustion engine configured by providing a spacer partitioned into
In the spacer part in the middle of the flow direction of the cooling water, an introduction means for introducing a part of the cooling water flowing through the outer passage upward from the upper part of the spacer part to the inner passage is provided.
The introduction means is formed on the side surface of the spacer facing the outer passage so as to extend obliquely upward from the upstream side to the downstream side in the flow direction of the cooling water, and directs the cooling water flowing through the outer passage upward. An inclined base part, and an opening part formed at the upper part of the spacer and connected to the end of the inclined base part, for introducing cooling water directed upward into the inner passage,
The upper end of the spacer, the cooling of the inner combustion engine characterized in that the cooling water flowing through the inclined base portion has a ridge protruding into the outer passage to suppress the entering into the inner passage apparatus.

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